Bobbin assembly with backlash preventing structure

ABSTRACT

The combination of a bobbin assembly and a support for the bobbin assembly. The bobbin assembly has a core around which a supply of thread can be wrapped. The core has a rotational axis. The bobbin assembly further has a first flange with first and second oppositely facing surfaces. The first surface bounds a storage space for thread wrapped around the core. The first flange has at least one projection from the second surface. The support has a third surface facing the second surface and bearing against the at least one projection for limiting movement of the spool in a direction substantially parallel to the rotational axis with the bobbin assembly operatively connected to the support.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to bobbin assemblies for supplies ofthread as used on different sewing machines and, more particularly, to abobbin assembly having structure which cooperates with a support for thebobbin assembly to prevent backlash of thread due to overrunning.

[0003] 2. Background Art

[0004] Bobbins are used for thread supplies on a wide range of sewingequipment. Typically, the bobbin has a core with a rotational axis andaxially spaced flanges which bound a storage space for thread wrappedaround the core. The bobbin is mounted on a support for rotation aroundthe core axis. By rotating the bobbin, thread wrapped around the core iscontrollably paid out.

[0005] Ideally, the bobbin is guidingly rotated during operation withoutany significant resistance as might cause uneven line distribution or,in a worse case, jamming of the bobbin. While smooth rotation of thebobbin is desirable during sewing operations, the unimpeded rotation ofthe bobbin potentially causes thread backlash. Ideally, as the machineryis stopped, the bobbin rotation simultaneously ceases. However, due tothe free rotation of the bobbin, the momentum of the rotating bobbincauses it to continue to rotate which could produce a backlash in thethread. This may require that the machinery be shut down to allow thebacklash to be eliminated. Severely backlashed thread may have to becut. Potentially, there is a significant loss of operating time, as wellas the inconvenience of having to manually remedy the backlashsituation. Severe backlashing may require replacement of the bobbin witha bobbin having a new supply of thread. Consequently, significantamounts of thread may be wasted.

[0006] Potentially of greater significance is the fact that a slackenedthread resulting from overrunning of the bobbin may cause at leasttemporary defective stitching after the equipment is re-started. Thismay lead to defective product that may have to either be restitched ordestroyed.

[0007] To address this problem, it is known to install disk-like springelements on a case which confines the bobbin into its operativeposition. These springs have deflectable arms which produce a frictionalbias force on the bobbin. This force is preferably controlled so that itdoes not significantly impeded rotation of the bobbin during a sewingoperation yet produces enough resistance that the bobbin will notcontinue to rotate once the equipment is stopped as might cause threadbacklash.

SUMMARY OF THE INVENTION

[0008] In one form, the invention is directed to the combination of abobbin assembly and a support for the bobbin assembly. The bobbinassembly has a core around which a supply of thread can be wrapped. Thecore has a rotational axis. The bobbin assembly further has a firstflange with first and second oppositely facing surfaces. The firstsurface bounds a storage space for thread wrapped around the core. Thefirst flange has at least one projection from the second surface. Thesupport has a third surface facing the second surface and bearingagainst the at least one projection for limiting movement of the spoolin a direction substantially parallel to the rotational axis with thebobbin assembly operatively connected to the support.

[0009] The combination may include a supply of thread wrapped around thecore. In one form, the first and second surfaces have substantially thesame area and the at least one projection occupies an area that is lessthan the area of the second surface.

[0010] The at least one projection may be formed as one piece with thefirst flange or separately formed and fixedly attached to the firstflange.

[0011] In one form, the bobbin assembly has a second flange that isspaced along the rotational axis from the first flange so that the firstand second flanges cooperatively bound the thread storage space.

[0012] In one form, there are a plurality of projections from the secondsurface which bear against the third surface of the bobbin assembly,with the bobbin assembly operatively connected to the support.

[0013] The at least one projection may be in the form of a ridge.

[0014] The projection may be defined by roughening the second surface.

[0015] The at least one projection may be a projecting post.

[0016] The at least one projection may be defined by an element embeddedin the first flange.

[0017] The first flange and at least one projection may be made from thesame material or different materials.

[0018] In one form, the at least one projection is repositionablerelative to the first flange, as by bending.

[0019] The at least one projection may be made from a shape-retentivematerial that can be selectively formed and maintained in a plurality ofdifferent configurations.

[0020] The support may be a bobbin basket and/or a bobbin case.

[0021] The bobbin basket may include a post which projects into thecore. The bobbin assembly moves around the post as the bobbin basketmoves around the rotational axis.

[0022] The invention is also directed to a bobbin assembly as describedabove, for mounting to a support.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023]FIG. 1 is a partially schematic, exploded, partial cross-sectionalview of a bobbin assembly with projections on spaced flanges thereon,according to the present invention, and with the bobbin assemblyoperatively connected to a bobbin basket, a bobbin case, and a looptaker;

[0024]FIG. 2 is a side elevation view of the bobbin assembly in FIG. 1with a supply of thread wrapped therearound;

[0025]FIG. 3 is a perspective view of a bobbin assembly with analternative form of projection on one flange thereof, according to thepresent invention;

[0026]FIG. 4 is a perspective view of a flange on the inventive bobbinassembly with another form of projection thereon;

[0027]FIG. 5 is a side elevation view of the flange in FIG. 4;

[0028]FIG. 6 is a view as in FIG. 4 of a still further form ofprojection which is embedded in the flange, according to the invention;

[0029]FIG. 7 is a cross-sectional view of the flange taken along line7-7 of FIG. 6;

[0030]FIG. 8 is a view as in FIG. 4 of a further modified form ofprojection, according to the present invention;

[0031]FIG. 9 is a view as in FIG. 8 of a further modified form ofprojection, according to the present invention;

[0032]FIG. 10 is a view as in FIG. 9 with a still further form ofprojection, according to the present invention;

[0033]FIG. 11 is a cross-sectional view of the flange taken along line11-11 of FIG. 10;

[0034]FIG. 12 is a view as in FIG. 10 of a still further modified formof projection, according to the present invention;

[0035]FIG. 13 is a side elevation view of the flange in FIG. 12;

[0036]FIG. 14 s a view as in FIG. 12 of a still further modified form ofprojection, according to the invention;

[0037]FIG. 15 is a view as in FIG. 14 of a still further modified formof projection, according to the present invention; and

[0038]FIG. 16 is a side elevation of the flange of FIG. 15.

DETAILED DESCRIPTION OF THE DRAWINGS

[0039] In FIG. 1, a sewing machine assembly is shown at 10 and consistsof a bobbin basket 12 and a cooperating bobbin case 14 which are matableto produce a compartment 16 for one form of bobbin assembly 18,according to the present invention. The bobbin basket 12 has acup-shaped body 20 with a post 22 projecting upwardly therefrom forpassage through a hollow sleeve 23 depending from a top wall 26 and acontiguous opening 24 through the top wall 26 of the cup-shaped bobbincase 14. The post 22 is directed through the sleeve 23 fully so as to beexposed at the top of the wall 26. A latch assembly 30 is operable toengage a notch 32 in the post 22 to prevent separation of the matedbobbin case 14 and bobbin basket 12, as with the bobbin assembly 18operatively connected thereto and captive therebetween. A conventionalloop taker 34 is operably associated with the joined bobbin basket 12and bobbin case 14 and is useable in conventional manner, as well knownto those skilled in this art.

[0040] The bobbin assembly 18, as seen also in FIG. 2, consists of acylindrical core 36 around which a supply of thread 38 is wrapped. Thepost 22 extends through the core 36 so that the bobbin assembly 18 isrotatable guidingly around the sleeve 23 about an axis 40 relative tothe bobbin basket 12 and bobbin case 14.

[0041] The bobbin assembly 18 further consists of disk-shaped, first andsecond flanges 42, 44, at axial ends of the core 36 and cooperativelybounding a thread storage space 46.

[0042] The bobbin assembly construction may vary considerably in termsof its shape and composition. As one example, the entire bobbin assembly18 can be molded or otherwise formed from one piece of plastic.Alternatively, the bobbin assembly 18 can be made from metal. As a stillfurther alternative, the flanges 42, 44 can be made from a differentmaterial than the core 36. It is known, for example, to make the flanges42, 44 from a paper-type material.

[0043] The bobbin basket 12 and bobbin case 14 cooperatively define asupport for the bobbin assembly 18. The flange 42 has a first surface 48that bounds the storage space 46, and an oppositely facing secondsurface 50. With the bobbin assembly 18 operatively connected as in FIG.1, the first surface 48 faces a third surface 52 on the bobbincase/support 14.

[0044] The flange 44 has a surface 54 bounding the storage space 46 andan oppositely facing surface 56 which is in proximity to an oppositelyfacing surface 58 on the bobbin basket/support 12 with the bobbinassembly 18 operatively connected as in FIG. 1.

[0045] According to the invention, one or both of the surfaces 50, 56has at least one projection 60 , and in this case a plurality ofprojections 60. The projections 60 shown are fiber-like projections 60which are either integrally formed with the flanges 42, 44 or separatelyadhered thereto, as by an adhesive. The fiber-like projections 60 may beintegrally formed in a molding operation or attached as part of a sheet,or individually, as by an adhesive. The fiber-like projections 60 may bemade from plastic, metal, or virtually any other type of material havingsufficient integrity to remain reasonably intact after use in thisenvironment, as described below. The projections 60 might be made frommetal, or other material that is embedded in the flanges 42, 44.

[0046] The projections 60 on the first flange 42 bear against the bobbincase surface 52, whereas the projections 60 on the flange 44 bearagainst the surface 58 on the bobbin basket 12, with the bobbin assembly18 operatively connected as in FIG. 1. The projections 60 aredimensioned so that, while they bear against the surfaces 52, 58 as thebobbin assembly 18 is rotated around the axis 40 in operation, they donot significantly impede the rotation of the bobbin assembly 18 relativeto the bobbin basket 12 and bobbin case 14. At the same time, theprojections 60 produce enough resistance to prevent overrunning of thebobbin assembly 18, once the machinery is stopped and thread is nolonger being drawn off of the bobbin assembly 18 as might otherwiseproduce backlash. The projections 60 can be made of a dimension toeither be maintained in their straight configuration or bent partiallytowards the surface from which they project, as shown for theprojections 60 acting against the bobbin case surface 52 in FIG. 1. Theprojections 60 could also be configured to be bent against the surfacefrom which they project.

[0047] In FIG. 3, a bobbin assembly 70 is shown with the same generalconstruction as the bobbin assembly 18 and has a flange 72 with asurface 74 and a plurality of cantilevered, post-like projections 76from the surface 74, at spaced locations, to bear against a facingsupport surface, such as those 52, 58, previously described. As in allembodiments described herein, the bobbin assembly 70 may be made fromvirtually any material, with the projections 76 likewise being made fromany material that facilitates sliding movement against either of thesupport surfaces 52, 58 and which produces enough resistance to avoidoverrunning. The projections 76 may be relatively rigid or somewhatflexible so as to be bendable during operation.

[0048] In FIGS. 4 and 5, an alternative form of projection is shown onan exemplary flange 78 that may be useable on a bobbin basket tocooperative with a support surface. The flange 78 has a surface 80 whichsupports a layer 82 having projections 84 thereon. The layer 82 may bemaintained on the flange 78 by an adhesive 86. The projections 84 may berigid or in the form of fibers. As just one example, the layer 82 withthe projections 84 thereon may be a component typically used inhook-and-loop type fasteners systems. That is, the projections 84 may bepart of a hook-type element or loop-type element that is part of such afastener system.

[0049] In FIGS. 6 and 7, a flange 90 is shown with ridge-likeprojections 92 that are embedded in the flange 90. As just one example,the material defining the flange 90 may be plastic, which is moldedaround each projection 92. Alternatively, the projections 92 may befrictionally held in place or held in place by an adhesive. Theprojections 92 shown have concave outer surfaces 94 which bear on acooperating support surface. The number, shape and configuration of theprojections 92 in FIGS. 6 and 7 may vary from that shown.

[0050] In FIGS. 8 and 9, separate flanges 100, 102 are shown withintegrally formed ridge-like projections 104, 106 from surfaces 108, 110on the flanges 100, 102. The projections 104 have a curved shape, withthe projection 106 having a continuous spiral shape. The projections104, 106 might be separately formed and attached to the flanges 100,102.

[0051] In FIGS. 10 and 11, a flange 116 is shown with projections 118defined on a surface 120 thereof. In this case, the projections areformed by roughening the surface 120 by any means known to those skilledin this art.

[0052] In FIG. 14, a flange 130 is shown with a surface 132 havinganother form of projection, including long and short, generallystraight, ridge-like projections, 134, 136. As in all embodiments, theprojections 134, 136 may be integrally formed, molded in place, orattached as by an adhesive.

[0053] In FIGS. 12 and 13, a flange 140 is shown with projections 142 inthe form of spring-type elements with offset free ends 144. The freeends 144 are biased upwardly and are urged under a captive forceslightly downwardly towards a flange surface 146 from which they projectwith the bobbin assembly on which the flange 140 is provided operativelyconnected to a support therefor.

[0054] One or both of the projections 142 shown may be made from ashape-retentive material, such as thin metal, which can be placed andmaintained in a plurality of different configurations, as shown forexample in dotted lines in FIG. 13, to thereby vary the resistive force.

[0055] In FIGS. 15 and 16, a flange 152 is shown with a pair ofprojections 154, 156 from a surface 158. The projection 154 has an end160 secured to the surface 158, as by a fastener 162, and a free end 164that is bent upwardly, and preferably reconfigurable as the projections142 in FIGS. 12 and 13.

[0056] The projection 156 has a fastener 166 which maintains a centralportion thereof attached to the surface 158, and spaced free ends 168,170, corresponding to those 144 previously described, and projectingupwardly from the surface 158 to be biased against a cooperating supportsurface. The free ends may be reconfigurable and made from ashape-retentive material that can be reconfigured, or a spring-typematerial which tends towards a single configuration.

[0057] In all the embodiment shown, the bobbin assemblies, according tothe present invention, can be operatively connected so that theprojections on the flange surfaces thereon abut to a surface on acooperating support to guide, yet not significantly inhibit, rotation ofthe bobbin relative to the support. The projections shown are butexemplary of the many different types of projections contemplated by theinvention. It is desirable that, regardless of the shape of theprojection, the projection(s) occupy an area on its associated flangesurface that is less than the area of that flange surface.

[0058] The foregoing disclosure of specific embodiments is intended tobe illustrative of the broad concepts comprehended by the invention.

1. In combination: a) a bobbin assembly comprising: i) a core aroundwhich a supply of thread can be wrapped, the core having a rotationalaxis; and ii) a first flange having first and second oppositely facingsurfaces, the first surface bounding a storage space for thread wrappedaround the core, the first flange comprising at least one projectionfrom the second surface; and b) a support for the bobbin assembly, saidsupport comprising: i) a third surface facing the second surface andbearing against the at least one projection and limiting movement of thebobbin assembly in a direction substantially parallel to the rotationalaxis with the bobbin assembly operatively connected to the support. 2.The combination according to claim 1 further comprising a supply ofthread wrapped around the core.
 3. The combination according to claim 1wherein the first and second surfaces have substantially the same areaand the at least one projection occupies an area that is less than thearea of the second surface.
 4. The combination according to claim 1wherein the at least one projection is formed as one piece with thefirst flange.
 5. The combination according to claim 1 wherein the atleast one projection is formed separately from and fixedly attached tothe first flange.
 6. The combination according to claim 1 wherein thebobbin assembly further comprises a second flange that is spaced alongthe rotational axis from the first flange so that the first and secondflanges cooperatively bound the thread storage space.
 7. The combinationaccording to claim 1 wherein there are a plurality of projections fromthe second surface which bear against the third surface with the bobbinassembly operatively connected to the support.
 8. The combinationaccording to claim 1 wherein the at least one projection comprises aformed ridge.
 9. The combination according to claim 1 wherein the atleast one projection is defined by roughening the second surface. 10.The combination according to claim 1 wherein the at least one projectioncomprises a projecting post.
 11. The combination according to claim 1wherein the at least one projection comprises an element that isembedded in the first flange.
 12. The combination according to claim 5wherein the first flange and at least one projection are made from thesame material.
 13. The combination according to claim 5 wherein thefirst flange and the at least one projection are made from differentmaterials.
 14. The combination according to claim 1 wherein the at leastone projection is repositionable relative to the first flange.
 15. Thecombination according to claim 14 wherein the at least one projection isrepositionable by bending relative to the first flange.
 16. Thecombination according to claim 1 wherein the support comprises a bobbinbasket.
 17. The combination according to claim 16 wherein the bobbinbasket comprises a post which projects into the core, the bobbin basketmoving around the post as the bobbin basket moves around the rotationalaxis.
 18. The combination according to claim 1 wherein the supportcomprises a bobbin case.
 19. The combination according to claim 14wherein the at least one projection is made from a shape-retentivematerial which can be placed and maintained in a plurality of differentconfigurations.
 20. A bobbin assembly for a supply of thread, saidbobbin assembly comprising: a core around which a supply of thread canbe wrapped, the core having a rotational axis; and a first flange havingfirst and second oppositely facing surfaces, the first surface boundinga storage space for thread wrapped around the core, the first flangecomprising at least one projection from the second surface.
 21. Thebobbin assembly for a supply of thread according to claim 20 wherein thefirst and second surfaces have substantially the same area and the atleast one projection occupies an area that is less than the area of thesecond surface.
 22. The bobbin assembly for a supply of thread accordingto claim 20 wherein the at least one projection comprises a formedridge.
 23. The bobbin assembly for a supply of thread according to claim20 wherein the at least one projection is defined by roughening thesecond surface.
 24. The bobbin assembly for a supply of thread accordingto claim 20 wherein the at least one projection comprises a projectingpost.
 25. The bobbin assembly for a supply of thread according to claim20 wherein the first flange and the at least one projection are madefrom different materials.
 26. The bobbin assembly for a supply of threadaccording to claim 20 wherein the at least one projection isrepositionable by bending relative to the first flange.